Rules Aren’t Physics. The rules of the game are meant to provide a fun game experience, not to describe the laws of physics in the worlds of D&D, let alone the real world. Don’t let players argue that a bucket brigade of ordinary people can accelerate a spear to light speed by all using the
Ready action to pass the spear to the next person in line. The Ready action facilitates heroic action; it doesn’t define the physical limitations of what can happen in a 6-second combat round.
The Game Is Not an Economy. The rules of the game aren’t intended to model a realistic economy, and players who look for loopholes that let them generate infinite wealth using combinations of spells are exploiting the rules.
Combat Is for Enemies. Some rules apply only during combat or while a character is acting in Initiative order. Don’t let players attack each other or helpless creatures to activate those rules.
Rules Rely on Good-Faith Interpretation. The rules assume that everyone reading and interpreting the rules has the interests of the group’s fun at heart and is reading the rules in that light.